Cr-Ni-Mo-Ti马氏体时效不锈钢热锻环粗晶粒的遗传及细化  

Inheritance and refinement of coarse grains in hot forging rings of a Cr-Ni-Mo-Ti maraging stainless steel

作　　者：丁雅莉[1] 高齐[1] 王敖 Ding Yali;Gao Qi;Wang Ao(Research Instirute of Special Steels,Central Iron&Steel Research Institute Co.,Ltd.,Beijing 100081,China)

机构地区：[1]钢铁研究总院有限公司特殊钢研究院,北京100081

出　　处：《金属热处理》2025年第1期169-173,共5页Heat Treatment of Metals

摘　　要：针对Cr-Ni-Mo-Ti马氏体时效不锈钢热锻环的晶粒粗大问题,研究了锻态粗晶的遗传温度范围,确定了细化晶粒的再结晶温度(T_(re)),同时研究了重复加热/冷却的晶粒细化效应以及其对力学性能的影响。结果表明:在试验钢Af以上很宽的温度范围内遗传锻态粗晶,950℃附近固溶处理后形成晶界完全封闭、明显细化的奥氏体晶粒,表明再结晶温度T_(re)≈950℃,进一步提高固溶温度时晶粒持续长大;略低于950℃重复加热/冷却时晶界大幅迁移形成晶界未封闭、尺寸明显细化的晶粒,在950℃重复加热/冷却仍有细化晶粒作用,但进一步提高温度重复加热/冷却时的晶粒细化作用减弱,1050℃重复加热/冷却不再有晶粒细化效果;875℃重复加热/冷却时细化晶粒能明显改善其冲击性能,但抗拉强度和屈服强度下降,表现出强度随晶粒尺寸细化而下降的现象;925℃和975℃(T_(re)附近)加热/冷却1次的强度和韧性与875℃加热/冷却3次的接近,虽然重复加热/冷却时晶粒略有细化,但力学性能无明显变化。In order to solve the problem of coarse grains remained in hot forging rings of a Cr-Ni-Mo-Ti maraging stainless steel,the temperature range of inheriting of forged coarse grains was investigated,and the recrystallization temperature for grain size refinement was determined.Moreover,the effect of repeated solution treatment on the grain size refinement and mechanical properties was determined.The results show that the forged coarse grains are inherited in a wide temperature range above Af of the steel.After solution treatment near 950 ℃,the austenite grains with completely closed grain boundaries and obvious refinement are formed,indicating that the recrystallization temperature T_(re) is approximately equal to 950 ℃,moreover,further increasing the solution temperature leads to grain growth.Repeated heating and cooling slightly below 950 ℃ lead to large grain boundary migration and forming the fine grain with open boundries.The repeated heating and cooling at 950 ℃ can still fine the grains,while the effect is weakened with the further increase of temprature,untill the effect vanish at 1050 ℃.The grain refinement by repeated heating and cooling at 875 ℃ significantly improves the impact properties,but the tensile strength and yield strength decrease,showing that the strength decreases with the grain refinement.The strength and toughness when heating and cooling once at 925,975 ℃(near T_(re)) are close to those of repeated heating and cooling for 3 cycles at 875 ℃,while the grains are slightly refined with the increase of repeated heating and cooling times,and there is no significant change in mechanical properties.

关 键 词：马氏体时效不锈钢 锻态粗晶 粗晶遗传 再结晶 重复加热/冷却 

分 类 号：TG142.71[一般工业技术—材料科学与工程]